3D printing process and equipment for short fiber reinforced resin

Abstract

The invention belongs to the technical field of 3D printing, particularly relates to a 3D printing process and equipment for short fiber reinforced resin, and aims to solve the problems that when an existing long fiber bundle is axially broken, spirally-arranged short fibers cannot provide vertical acting force, so that the hindering effect of the short fibers on internal cracks can be reduced; in order to solve the problem that in the prior art, a nozzle is easily blocked due to the fact that short fibers are axially distributed around the long fibers, the following scheme is provided: a reinforced resin wire containing the short fibers is subjected to hot melting, the orientation of the hot-molten reinforced resin wire containing the short fibers is adjusted through a runner, and the heated and molten resin contains the short fibers and is impregnated among the long fibers; and after the orientation of the short fibers is adjusted through the flow channel, the short fibers obliquely face the long fibers in a radial shape, then the short fibers are printed on the printing platform through the 3D printing nozzle, the acting force of the short fibers in the axial direction of the continuous fibers can be enhanced, blockage can be avoided, accordingly, key parts are protected against damage, and the service life of equipment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a 3D printing process and equipment of short fiber reinforced resin. Background Art

[0002] Continuous fibers mainly bear tensile loads, but due to their brittleness, fracture may occur first during the stretching process of the printed part. Adding short fibers to assist in strengthening the matrix, improve its strength, and slow down the fracture of the fibers. Under tensile loading, the continuous fibers and the matrix will share the strain, but the fracture of the continuous fibers usually occurs before the matrix. As the stretching progresses, the cracks inside the print extend, but due to the reinforcement of the short fibers, the matrix can withstand greater forces and improve the stress concentration effect, thereby delaying the fracture of the print. On the one hand, the expansion trend of the cracks inside the print will be hindered to a certain extent by the short fibers. On the other hand, due to the reinforcement of the short fibers on the matrix, the matrix of the print can withstand greater forces, and the stress concentration effect around the broken fibers will also be improved to a certain extent.

[0003] For example, a composite material 3D printing device for realizing the Z-direction cross-linking effect using short fibers provided in 202310388345.8 can effectively control the spiral arrangement of short chopped carbon fibers in the resin by using a rotating magnetic field, thereby improving the mechanical properties of the long-short fiber co-reinforced composite material. However, when the long fiber bundle is arranged in spiral, the spirally arranged short fibers cannot provide vertical force when axial fracture occurs, thereby reducing the hindering effect of the short fibers on internal cracks.

[0004] And arranging the short fibers around the long fibers axially will make the nozzle more likely to be blocked. When the nozzle is blocked, first stop the 3D printer to prevent the blockage from getting worse and let the print nozzle cool down for a while. This will help solidify or solidify the melt in the nozzle, making it easier to clean and remove the nozzle from the 3D printer. This usually involves loosening the nozzle fixing screw and removing it from the hot end, carefully cleaning the blockage in the nozzle with appropriate tools (such as needles, pliers, etc.). This may require some patience and careful operation to ensure that the nozzle is not damaged, thereby affecting printing efficiency. Summary of the invention

[0005] The present invention provides a 3D printing process and equipment for short fiber reinforced resin, which solves the shortcomings in the prior art that when the long fiber bundle produces axial fracture, the spirally arranged short fibers cannot provide vertical force, thereby reducing the barrier effect of the short fibers on internal cracks; and the axial arrangement of the short fibers around the long fibers will more easily cause the nozzle to be blocked.

[0006] The present invention provides the following technical solutions:

[0007] On the one hand, the present application provides a 3D printing process for short fiber reinforced resin, in which resin wires reinforced with short fibers are hot-melted, and the orientation of the hot-melt resin wires reinforced with short fibers is adjusted through a flow channel. The heated and melted resin containing the short fibers is impregnated between the long fibers, and after the orientation of the short fibers is adjusted through the flow channel, the short fibers are radially inclined toward the long fibers, and then printed onto the printing platform through a 3D printing nozzle.

[0008] On the other hand, the present application provides a printing device, characterized in that it includes a continuous fiber roller for providing continuous fiber wires, a short fiber resin wire roller for providing resin wires reinforced with short fibers, and a printing nozzle installed on the printing device that can change its position in the x-axis and y-axis directions, a printing platform capable of adjusting the z-axis height is installed below the printing nozzle, the printing nozzle includes a first nozzle for conveying short fiber reinforced resin wires and a second nozzle for conveying continuous fibers, the first nozzle is connected to a vertical flow channel of the resin wire arranged on the outside of the second nozzle, and the vertical flow channel of the resin wire and the second nozzle are formed with a conical confluence.

[0009] As a further improvement of the above scheme,

[0010] Preferably, the vertical flow channel is a curved flow channel, and the curved flow channel smoothly transitions to the tapered confluence.

[0011] Preferably, an electric control switch for cutting off the first nozzle and the vertical flow channel is installed at the end of the first nozzle.

[0012] Preferably, a piston ring is installed on the top of the vertical direct current channel, and the piston ring is fixedly connected to the driven rod, and the driven rod is slidably connected to the heat dissipation member on the upper part of the second nozzle through an elastic member, and a vertically arranged first rack and a second rack are installed on one side of the driven rod, and a driving cylinder is installed on one side of the heat dissipation member, and the output shaft of the driving cylinder is fixedly connected to the driving rod through a telescopic rod, and a vertically arranged third rack and a fourth rack are installed on the driving rod, the first rack is meshed with the first gear, the first gear is meshed with the second gear, the second gear and the first ratchet mechanism are located on the same rotating shaft, the first ratchet mechanism cooperates with the third rack to drive the first rack to move upward, the second rack is meshed with the third gear, the third gear is meshed with the fourth gear, and the fourth gear and the second ratchet mechanism are located on the same rotating shaft, the second ratchet mechanism cooperates with the fourth rack to drive the first rack to move downward, and two clamping cylinders for clamping continuous fibers at both ends of the first nozzle are installed on the driving rod.

[0013] Preferably, a limit cylinder is installed on the second nozzle, a limit rod is installed on the output shaft of the limit cylinder, and a limit groove is provided on the driven rod.

[0014] Preferably, the first ratchet mechanism and the second ratchet mechanism have the same structure and both include an inner ratchet and an outer toothed ring, and the outer toothed ring drives the inner ratchet to rotate by cooperating with a pawl on the inner ratchet through the ratchet teeth.

[0015] Preferably, the number of teeth on the first gear is greater than that on the second gear, the number of teeth on the fourth gear is greater than that on the third gear, the number of teeth on the outer gear ring of the first ratchet mechanism matches the number of teeth on the second gear, and the number of teeth on the outer gear ring of the second ratchet mechanism matches the number of teeth on the fourth gear.

[0016] Preferably, one of the clamping cylinders is located below the first nozzle, and the other is located above the first nozzle. The first clamping arm and the second clamping arm of the clamping cylinder are provided with clamping members via elastic telescopic rods. A first shearing arm is provided on the upper part of the first clamping arm, and a second shearing arm is provided on the upper part of the second clamping arm of the clamping cylinder. The first shearing arm and the second shearing arm avoid each other.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention.

[0018] In the present invention, the short fibers are radially inclined toward the long fibers, and then printed onto the printing platform by a 3D printing nozzle. The orientation of the short fibers is adjusted by the device so that the short fibers are radially inclined toward the long fibers. Therefore, the action direction of the short fibers is not only along the length direction of the continuous fibers, but the short fibers also exert force on the axial direction of the continuous fibers.

[0019] The driving rod is driven to move up and down by the telescopic cylinder, and the driving rod drives the two clamping cylinders to move up and down, and the piston assembly is driven to move up and down together during the movement, and the number of teeth of the first gear is greater than the number of teeth of the second gear, and the number of teeth of the outer gear ring of the first ratchet mechanism is adapted to the number of teeth of the second gear. When the driving rod moves upward, the driven rod moves upward faster, so that more negative pressure is generated in the curved flow channel, so that the pressure and holding effect of the internal molten material is reduced when the continuous fiber is pulled upward;

[0020] When the driving rod moves downward, the driving rod moves downward faster, so that a downward pulling force is first exerted on the lower wire to form a breakthrough, and then the piston assembly provides a downward assisting force to the melt;

[0021] The blockage is loosened by continuous up and down movements, and an elastic telescopic rod is provided at the driven rod so that when the internal force is large under blockage conditions, the vertical displacement of the piston assembly and the clamping cylinder will be relatively small. As the blockage is gradually unblocked, the internal force will be smaller, causing the vertical displacement of the piston assembly and the clamping cylinder to gradually increase until the blockage is completely unblocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A schematic diagram of the structure provided by an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the print head structure provided by an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of a partially enlarged structure of a printing nozzle provided in an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of the structure of the first clamping arm and the second clamping arm provided in an embodiment of the present invention;

[0026] Figure 5 A schematic diagram of the structure of a first rack, a third rack, a first gear, a second gear and a first ratchet mechanism provided by an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the structure of a second rack, a fourth rack, a third gear, a fourth gear and a second ratchet mechanism provided by an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the distribution of short fibers when the continuous fibers provided in an embodiment of the present invention are broken.

[0029] Reference numerals:

[0030] 1. Staple fiber resin wire roller; 2. Resin wire reinforced with staple fibers; 3. Continuous fibers; 4. Continuous fiber roller; 5. Printing platform; 6. Driving cylinder; 7. Heat sink; 8. Clamping cylinder; 9. Second nozzle; 10. First nozzle; 11. Follower rod; 12. Driving rod; 13. Limiting cylinder; 14. Vertical flow channel; 15. Piston ring; 16. Conical confluence; 17. First clamping arm; 18. First shearing arm; 19. Second shearing arm; 20. Second clamping arm; 21. Clamping member; 22. First gear; 23. Second gear; 24. Third rack; 25. First ratchet mechanism; 26. First rack; 27. Third gear; 28. Fourth gear; 29. ​​Fourth rack; 30. Second ratchet mechanism; 31. Second rack; 32. Staple fibers. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0032] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms, "connection" and "installation" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. In addition, "connection" can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed" means that they are connected to each other and the relative position relationship after connection remains unchanged. The directional terms mentioned in the embodiments of the present invention, such as "inside", "outside", "top", "bottom", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0033] In the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0034] In the embodiments of the present invention, "and / or" is only a description of the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0035] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present invention. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0036] Example

[0037] Reference Figure 1-Figure 7 , a 3D printing process for short fiber reinforced resins,

[0038] The resin wire material 2 reinforced with short fibers is hot-melted, and the orientation of the hot-melt resin wire material 2 reinforced with short fibers 32 is adjusted through a flow channel. The heated and melted resin containing the short fibers 32 is impregnated between the long fibers. After the orientation of the short fibers 32 is adjusted through the flow channel, the short fibers 32 are radially inclined toward the long fibers, and then printed onto the printing platform 5 through a 3D printing nozzle. The orientation of the short fibers 32 is adjusted through the equipment, so that the short fibers 32 are radially inclined toward the long fibers. Therefore, the action direction of the short fibers 32 is not only along the length direction of the continuous fibers 3, but the short fibers 32 also have an axial force on the continuous fibers 3.

[0039] A 3D printing device for short fiber reinforced resin, used to implement the printing process as claimed in claim 1, comprising a continuous fiber roller 4 for providing continuous fiber wire, a short fiber resin wire roller 1 for providing a resin wire 2 containing short fiber reinforcement, and a printing nozzle installed on the printing device and capable of changing its position in the x-axis and y-axis directions, a printing platform 5 capable of adjusting the z-axis height is installed below the printing nozzle, the printing nozzle comprises a first nozzle 10 for conveying a short fiber reinforced resin wire and a second nozzle 9 for conveying continuous fiber 3, an electric control switch for cutting off the first nozzle 10 and the vertical flow channel is installed at the end of the first nozzle 10, the first nozzle 10 is connected to a resin wire vertical flow channel 14 arranged outside the second nozzle 9, and the resin wire vertical flow channel 14 is connected to The second nozzle 9 is formed with a conical confluence 16, and the vertical flow channel 14 is a curved flow channel, which smoothly transitions with the conical confluence 16. A piston ring 15 is installed on the top of the vertical flow channel, and the piston ring 15 is fixedly connected to the driven rod 11. The driven rod 11 is slidably connected to the heat sink 7 on the upper part of the second nozzle 9 through an elastic member. A vertically arranged first rack 26 and a second rack 31 are installed on one side of the driven rod 11, and a driving cylinder 6 is installed on one side of the heat sink 7. The output shaft of the driving cylinder 6 is fixedly connected to the driving rod 12 through a telescopic rod. A vertically arranged third rack 24 and a fourth rack 29 are installed on the driving rod 12. The first rack 26 is meshed with the first gear 22, the first gear 22 is meshed with the second gear 23, and the second gear 23 is meshed with the first ratchet. The mechanism 25 is located on the same rotating shaft, the first ratchet mechanism 25 cooperates with the third rack 24 to drive the first rack 26 to move upward, the second rack 31 is meshed with the third gear 27, the third gear 27 is meshed with the fourth gear 28, the fourth gear 28 and the second ratchet mechanism 30 are located on the same rotating shaft, the second ratchet mechanism 30 cooperates with the fourth rack 29 to drive the first rack 26 to move downward, two clamping cylinders 8 for clamping the continuous fibers 3 at both ends of the first nozzle 10 are installed on the driving rod 12, a limiting cylinder 13 is installed on the second nozzle 9, a limiting rod is installed on the output shaft of the limiting cylinder 13, and a limiting groove is provided on the driven rod 11. The first ratchet mechanism 25 and the second ratchet mechanism 30 have the same structure and both include an inner ratchet and an outer toothed ring, and the outer toothed ring is connected by a ratchet The teeth cooperate with the pawl on the inner ratchet to drive the inner ratchet to rotate, the number of teeth of the first gear 22 is greater than the number of teeth of the second gear 23, the number of teeth of the fourth gear 28 is greater than the number of teeth of the third gear 27, the number of teeth of the outer gear ring of the first ratchet mechanism 25 is adapted to the number of teeth of the second gear 23, the number of teeth of the outer gear ring of the second ratchet mechanism 30 is adapted to the number of teeth of the fourth gear 28, one of the clamping cylinders 8 is located below the first nozzle 10, and the other is located above the first nozzle 10, the first clamping arm 17 and the second clamping arm 20 of the clamping cylinder 8 are equipped with a clamping member 21 through an elastic telescopic rod, the first clamping arm 17 is equipped with a first shearing arm 18, the second clamping arm 20 of the clamping cylinder 8 is equipped with a second shearing arm 19, and the first shearing arm 18 and the second shearing arm 19 avoid each other.

[0040] The working principle of the present application is that, through the design of the flow channel, the orientation of the resin containing short fibers 32 is adjusted along the flow channel after melting. By designing the curved flow channel, firstly, the flow channel is extended to facilitate the adjustment of the orientation of the short fibers 32, and secondly, the curved flow channel can smoothly transition with the tapered confluence 16, so that the orientation of the short fibers 32 can be adjusted, so that the short fibers 32 are radially inclined toward the long fibers. Therefore, the action direction of the short fibers 32 is not only along the length direction of the continuous fibers 3, but the short fibers 32 also exert force on the axial direction of the continuous fibers 3.

[0041] A piston assembly is also provided at the upper part of the curved flow channel. When the second nozzle 9 is blocked, the output shaft of the limit cylinder 13 is controlled to retract, the limit on the driven rod 11 is released, and the two clamping cylinders 8 are controlled to clamp the upper continuous fiber 3 and the lower wire. After clamping, the first shear arm 18 and the second shear arm 19 will cut the upper continuous fiber 3 and the lower wire. The driving rod 12 is driven by the telescopic cylinder to move up and down. The driving rod 12 drives the two clamping cylinders 8 to move up and down, and drives the piston assembly to move up and down together during the movement. The number of teeth of the first gear 22 is greater than the number of teeth of the second gear 23, and the number of teeth of the outer gear ring of the first ratchet mechanism 25 is adapted to the number of teeth of the second gear 23. When the driving rod 12 moves upward, the driven rod 11 moves upward faster, so that more negative pressure is generated in the curved flow channel, so that the pressure and holding effect of the internal molten material is reduced when the continuous fiber 3 is pulled upward;

[0042] The number of teeth of the fourth gear 28 is greater than the number of teeth of the third gear 27, and the number of teeth of the outer tooth ring of the second ratchet mechanism 30 is adapted to the number of teeth of the fourth gear 28. When the driving rod 12 moves downward, the driving rod 12 moves downward faster, so that a downward pulling force is first exerted on the lower wire to form a breakthrough, and then the piston assembly provides a downward assisting force to the melt, and the blockage is loosened through continuous up and down movements. By arranging an elastic telescopic rod at the driven rod 11, when the internal force is large in the case of blockage, the vertical displacement of the piston assembly and the clamping cylinder 8 will be relatively small. As the blockage is gradually unblocked, the internal force is smaller, so that the vertical displacement of the piston assembly and the clamping cylinder 8 will gradually increase until it is completely unblocked.

[0043] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention; the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A 3D printing process of short fiber reinforced resin, characterized in that: The resin wire reinforced with short fibers is hot-melted, and the orientation of the hot-melt resin wire reinforced with short fibers is adjusted through a flow channel. The heated and melted resin contains the short fibers and is impregnated between the long fibers. After the orientation of the short fibers is adjusted through the flow channel, the short fibers are radially inclined toward the long fibers, and then printed onto the printing platform through a 3D printing nozzle.

2. The printing device for the 3D printing process of short fiber reinforced resin according to claim 1, characterized in that: It includes a continuous fiber roller for providing continuous fiber wire, a short fiber resin wire roller for providing resin wire containing short fiber reinforcement, and a printing nozzle installed on the printing device and capable of changing its position in the x-axis and y-axis directions. A printing platform capable of adjusting the z-axis height is installed below the printing nozzle. The printing nozzle includes a first nozzle for conveying short fiber reinforced resin wire and a second nozzle for conveying continuous fiber. The first nozzle is connected to a vertical flow channel of the resin wire arranged on the outside of the second nozzle, and the vertical flow channel of the resin wire and the second nozzle are formed with a tapered confluence.

3. The printing device according to claim 2, characterized in that: The vertical flow channel is a curved flow channel, and the curved flow channel smoothly transitions to the tapered confluence port.

4. The printing device according to claim 3, characterized in that: An electric control switch for cutting off the first nozzle and the vertical flow channel is installed at the end of the first nozzle.

5. The printing device according to claim 4, characterized in that: A piston ring is installed on the top of the vertical direct current channel, and the piston ring is fixedly connected to the driven rod, and the driven rod is slidably connected to the heat dissipation member on the upper part of the second nozzle through an elastic member, and a vertically arranged first rack and a second rack are installed on one side of the driven rod, and a driving cylinder is installed on one side of the heat dissipation member, and the output shaft of the driving cylinder is fixedly connected to the driving rod through a telescopic rod, and a vertically arranged third rack and a fourth rack are installed on the driving rod, the first rack is meshed with the first gear, the first gear is meshed with the second gear, the second gear and the first ratchet mechanism are located on the same rotating shaft, the first ratchet mechanism cooperates with the third rack to drive the first rack to move upward, the second rack is meshed with the third gear, the third gear is meshed with the fourth gear, and the fourth gear and the second ratchet mechanism are located on the same rotating shaft, the second ratchet mechanism cooperates with the fourth rack to drive the first rack to move downward, and two clamping cylinders for clamping continuous fibers at both ends of the first nozzle are installed on the driving rod.

6. The printing device according to claim 5, characterized in that: The second nozzle is provided with a limit cylinder, the output shaft of the limit cylinder is provided with a limit rod, and the driven rod is provided with a limit groove.

7. The printing device according to claim 5, characterized in that: The first ratchet mechanism and the second ratchet mechanism have the same structure and both include an inner ratchet and an outer toothed ring. The outer toothed ring drives the inner ratchet to rotate by cooperating with the pawl on the inner ratchet through the ratchet teeth.

8. The printing device according to claim 5, characterized in that: The number of teeth of the first gear is greater than that of the second gear, the number of teeth of the fourth gear is greater than that of the third gear, the number of teeth of the outer gear ring of the first ratchet mechanism matches the number of teeth of the second gear, and the number of teeth of the outer gear ring of the second ratchet mechanism matches the number of teeth of the fourth gear.

9. The printing device according to claim 5, characterized in that: One of the clamping cylinders is located below the first nozzle, and the other is located above the first nozzle. The first clamping arm and the second clamping arm of the clamping cylinder are provided with clamping members via elastic telescopic rods. A first shearing arm is provided on the upper part of the first clamping arm, and a second shearing arm is provided on the upper part of the second clamping arm of the clamping cylinder. The first shearing arm and the second shearing arm avoid each other.

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